Scepter thief as a boon support or healer + rework venom trait to use the thief's healing power.
Longbow, greatsword or hammer ele with a mechanic that focus on using one or two elements sounds fun. Or make it so 1-5 skills being arcane/earth/fire/water/air instead of giving us the 4 usual element swaps.
Off-hand sword (or spear if they ever make it a land weapon) power duelist/dps guardian would be nice.
Staff support/healer warrior.
Greatsword rev for wvw frontline/aoe damage.